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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
	Tyrel Datwyler <tyreld@linux.ibm.com>,
	Alexey Kardashevskiy <aik@ozlabs.ru>,
	Tyrel Datwyler <tyreld@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH AUTOSEL 5.4 089/459] powerpc/pseries/vio: Fix iommu_table use-after-free refcount warning
Date: Fri, 14 Feb 2020 10:55:39 -0500
Message-ID: <20200214160149.11681-89-sashal@kernel.org> (raw)
In-Reply-To: <20200214160149.11681-1-sashal@kernel.org>

From: Tyrel Datwyler <tyreld@linux.vnet.ibm.com>

[ Upstream commit aff8c8242bc638ba57247ae1ec5f272ac3ed3b92 ]

Commit e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to
iommu_table") missed an iommu_table allocation in the pseries vio code.
The iommu_table is allocated with kzalloc and as a result the associated
kref gets a value of zero. This has the side effect that during a DLPAR
remove of the associated virtual IOA the iommu_tce_table_put() triggers
a use-after-free underflow warning.

Call Trace:
[c0000002879e39f0] [c00000000071ecb4] refcount_warn_saturate+0x184/0x190
(unreliable)
[c0000002879e3a50] [c0000000000500ac] iommu_tce_table_put+0x9c/0xb0
[c0000002879e3a70] [c0000000000f54e4] vio_dev_release+0x34/0x70
[c0000002879e3aa0] [c00000000087cfa4] device_release+0x54/0xf0
[c0000002879e3b10] [c000000000d64c84] kobject_cleanup+0xa4/0x240
[c0000002879e3b90] [c00000000087d358] put_device+0x28/0x40
[c0000002879e3bb0] [c0000000007a328c] dlpar_remove_slot+0x15c/0x250
[c0000002879e3c50] [c0000000007a348c] remove_slot_store+0xac/0xf0
[c0000002879e3cd0] [c000000000d64220] kobj_attr_store+0x30/0x60
[c0000002879e3cf0] [c0000000004ff13c] sysfs_kf_write+0x6c/0xa0
[c0000002879e3d10] [c0000000004fde4c] kernfs_fop_write+0x18c/0x260
[c0000002879e3d60] [c000000000410f3c] __vfs_write+0x3c/0x70
[c0000002879e3d80] [c000000000415408] vfs_write+0xc8/0x250
[c0000002879e3dd0] [c0000000004157dc] ksys_write+0x7c/0x120
[c0000002879e3e20] [c00000000000b278] system_call+0x5c/0x68

Further, since the refcount was always zero the iommu_tce_table_put()
fails to call the iommu_table release function resulting in a leak.

Fix this issue be initilizing the iommu_table kref immediately after
allocation.

Fixes: e5afdf9dd515 ("powerpc/vfio_spapr_tce: Add reference counting to iommu_table")
Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1579558202-26052-1-git-send-email-tyreld@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/powerpc/platforms/pseries/vio.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/vio.c b/arch/powerpc/platforms/pseries/vio.c
index 79e2287991dbb..f682b7babc09c 100644
--- a/arch/powerpc/platforms/pseries/vio.c
+++ b/arch/powerpc/platforms/pseries/vio.c
@@ -1176,6 +1176,8 @@ static struct iommu_table *vio_build_iommu_table(struct vio_dev *dev)
 	if (tbl == NULL)
 		return NULL;
 
+	kref_init(&tbl->it_kref);
+
 	of_parse_dma_window(dev->dev.of_node, dma_window,
 			    &tbl->it_index, &offset, &size);
 
-- 
2.20.1


  parent reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20200214160149.11681-1-sashal@kernel.org>
2020-02-14 15:54 ` [PATCH AUTOSEL 5.4 009/459] soc: fsl: qe: change return type of cpm_muram_alloc() to s32 Sasha Levin
2020-02-14 15:54 ` [PATCH AUTOSEL 5.4 042/459] powerpc/powernv/iov: Ensure the pdn for VFs always contains a valid PE number Sasha Levin
2020-02-14 15:55 ` [PATCH AUTOSEL 5.4 083/459] powerpc/powernv/ioda: Fix ref count for devices with their own PE Sasha Levin
2020-02-14 15:55 ` [PATCH AUTOSEL 5.4 084/459] powerpc/iov: Move VF pdev fixup into pcibios_fixup_iov() Sasha Levin
2020-02-14 15:55 ` [PATCH AUTOSEL 5.4 088/459] powerpc/papr_scm: Fix leaking 'bus_desc.provider_name' in some paths Sasha Levin
2020-02-14 15:55 ` Sasha Levin [this message]
2020-02-14 15:56 ` [PATCH AUTOSEL 5.4 154/459] net/wan/fsl_ucc_hdlc: reject muram offsets above 64K Sasha Levin
2020-02-14 15:58 ` [PATCH AUTOSEL 5.4 230/459] net/wan/fsl_ucc_hdlc: remove set but not used variables 'ut_info' and 'ret' Sasha Levin
2020-02-14 15:58 ` [PATCH AUTOSEL 5.4 263/459] soc: fsl: qe: remove set but not used variable 'mm_gc' Sasha Levin
2020-02-14 15:59 ` [PATCH AUTOSEL 5.4 341/459] KVM: PPC: Remove set but not used variable 'ra', 'rs', 'rt' Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 354/459] ide: remove set but not used variable 'hwif' Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 381/459] powerpc/ptdump: Fix W+X verification call in mark_rodata_ro() Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 382/459] powerpc/ptdump: Only enable PPC_CHECK_WX with STRICT_KERNEL_RWX Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 383/459] powerpc/sriov: Remove VF eeh_dev state when disabling SR-IOV Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 394/459] PCI/AER: Initialize aer_fifo Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 400/459] powerpc/pseries/lparcfg: Fix display of Maximum Memory Sasha Levin
2020-02-14 16:00 ` [PATCH AUTOSEL 5.4 401/459] selftests/eeh: Bump EEH wait time to 60s Sasha Levin
2020-02-14 16:01 ` [PATCH AUTOSEL 5.4 416/459] powerpc/mm: Don't log user reads to 0xffffffff Sasha Levin
2020-02-14 16:01 ` [PATCH AUTOSEL 5.4 430/459] powerpc: Do not consider weak unresolved symbol relocations as bad Sasha Levin

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